1. Field of Invention
The invention concerns pair of gear rimsxe2x80x94basic part of a design of rotary machines, in which the working process is carried out in chambers of variable volume formed as a result of interaction of pair eccentrically located gear rims, and can be used as in rotary machines with one rotor eccentrically located in static stator, and in rotary machines with several, in particular, with two, eccentrically located rotors. Declared pairs of gear rims can be used as a basic element of engines, pumps, compressors, hydro- and pneumatic motors, turbocompressors and other types of rotary machines.
2. Description of Prior Art
Known rotary machine xe2x80x9cRotary Power Devicexe2x80x9d, was filed on Oct. 22, 1936 by Thomas M. Gunn, patent U.S. Pat. No. 2,112,890. In this rotary machine working chambers are created in between interacting working surfaces of a pair of gear rims, placed on the inner surface of the outer rotor and on the outer surface of the inner rotor. The rotors are placed with eccentricity, the value of which equals the difference of radiuses of interacting sections of surfaces of interacting gear rims on the outer and inner rotors respectively.
The profile of contact surface of inner and outer gear rims has an axis of symmetry, bounded by conjugated arcs and represents the closed smooth curve consisting of n greater than 2 identical parts, conjugated among themselves. The identical part of contact surface of a gear rim is bounded by three conjugated arcs of a circle.
The machine contains inlet ports placed in end caps and discharge ports that are uniformly spaced with respect to the axis of rotation of spur wheel. Each of the discharge ports will move periodically into alignment with the exhaust passage opening through the circumference of the eccentric.
The existence of three conjugated arcs in identical part of the surface of gear rim in case of using discharge ports inside of inner rotor leads to serious loss of the yield and productivity of the machine. It is a result of the following feature of gear rim profiles that contains three arcs.
The chambers of variable volume are created in the area of conjugation of surfaces of different curvature. Abrupt change of the volume of created chamber is taking place in this area. If the port of slide-valve mechanism is placed in this area, on condition that this mechanism is functioning, while the port is wholly located within the chamber, then at the moment when the port is wholly located within the chamber, this chamber has a large volume that is totally lost for the working process, which lowers the yield and the productivity of the machine. For decreasing this volume it is possible to decrease the cross-section of the port, but it will cause an increased loss of energy, which means the decrease of yield of the machine.
More over during the creation of chambers the surfaces are increasing the most at the expanse of the surfaces with lower curvature. The lower the curvature radius of the surface of the inner rotor, the faster it opens at lower chamber volumes. In ideal case a flat surface totally opens at minimal chamber volume (although using flat surfaces leads to drastic loss of the productivity of the machinexe2x80x94patent EP 0 894 979 A1).
In the gear rim, identical part of which consists of three arcs, the arc of the smallest curvature is placed on the outer part of the inner rim, outside the point of identical part of the profile, that is nearest to the axes of the gear rim, in the optimal case (Patent WO 94/08140), it contains this point as the endpoint. Therefore slide-valve port has a sizable extraneous volume since it cannot be placed at a minimal distance from the axes of control gear, that is coincides with the axes of the gear rim. It leads to additional lowering of the yield and productivity of the rotary machine.
Patents similar to patent U.S. Pat. No. 2,112,890 are patents WO 94/08140 (JP 405202869A), EP 0 894 979 A1, JP 355023353A, JP 406280758A, all of them contain all the above mentioned drawbacks of gear rims with identical parts made of three conjugated arcs.
From the said above it follows, that it is impossible to create a gear rim with identical parts constructed from three conjugated arcs, that provide effective work of a control gear placed within the inner rotor.
The invention, briefly, concerns a profile of contact surface of a gear rim of a rotor and/or stator of a rotary machine, having no less than one pair of gear rimsxe2x80x94inner and outer, interacting with each other with creation of variable volume chambers, eccentrically located one inside the other with eccentricity e equal to the difference of the interacting surface radiuses. The claimed machine can have one pair of gear rims, interacting with each other with creation of variable volume chambers or several such pairs.
The profile of contact surface of inner and outer gear rim has an axis of symmetry, bounded by conjugated arcs and represents closed smooth curve, consisting of n greater than 2 identical parts, conjugated among themselves. Identical part of the inner gear rim is bounded by the arc of radius p1, conjugated at its ends with the arcs of radius q1 and of radius a+p1, where a=p1+q1. Arc of radius q1 conjugated at the other end with the arc of radius b+q1, where length b greater than 0. Arc of radius b+q1 is conjugated at the other end with the arc of radius a+p1 of adjacent identical part, which completes the gear rim profile.
Identical part of the outer gear rim is bounded by the arc of radius p2=p1+e, conjugated at its ends with the arcs of radius q2=axe2x88x92p2 and of radius a+p2. Arc of radius q2 conjugated at the other end with the arc of radius b+q2, which is conjugated at the other end with the arc of radius a+p2 of adjacent identical part, which completes the gear rim profile.
From the said above it follows, that center of arcs of radius p1 and p2 is arbitrary placed at the distance a greater than 0 from the center of arcs of radiuses q1, a+p1, q2, a+p2. The center of arcs of radiuses b+q1b+q2 is placed at the distances b greater than 0 and b+2a from the center of arcs of radiuses q1, a+p1, q2, a+p2 given and adjacent identical parts.
Within the inner gear rim slide-valve is placed. This slide-valve contains spool valve and slide-valve ports, at that slide-valve ports have exit into contact surface of the inner gear rim in the part of its profile of the radius b+q1.
Partition of the working surface profile into identical elements is a particular way of describing the profile. This invention defends the form of the profile of the rotor, bounded by conjugated arcs in a given order independently from grouping identical elements and without it.
The invention defends the profile of contact surface of a gear rim of the rotary machine, which provides for the creation of two types of chambers of variable volume. Achievingxe2x80x94more than a double distinction between volumes of processes, carried out in the machine,xe2x80x94expansion and compression, and only at the expense of the profile of contact surface of a gear rim. At the same time, the increase of specific productivity and yield of the rotary machine, both inner and outer gear rims are characterized by a uniform technique of construction; that considerably simplifies design, and manufacturing of rotors.
The invention defends the profile of contact surface of a gear rim of the rotary machine, with identical parts constructed from four conjugated arcs that provide effective work of a control gear placed within the inner rotor.